import re 
chaine = "2 ab 3 cd et 1450 : 20 , 99 3 a 158opg"
exp = re.compile("[0-9][0-9]+")
a = exp.search (chaine)
while a:
    print a.group()
    a=exp.search(chaine,a.end())


print (re.sub("[0-9][0-9]+","",chaine))

regex = re.compile("[0-9][0-9]+")
print regex.sub("",chaine)

print (re.sub(" +"," ",re.sub("[0-9][0-9]+","",chaine)))
